Such processes are in general known from a great variety of literature and are using a large number of diverging types of catalysts. However, these conventional industrial scale catalytic hydrogenation processes have the disadvantage that they are using rather pure hydrogen at high pressures such as disclosed in e.g. U.S. Pat. Nos. 4,628,130 and 4,346,240and German Pat. No. 1,768,262, and/or high temperatures or that they are using catalyst systems, which can only be removed from the desired product by laborious methods, which inevitably cause significant additional costs.
It will be appreciated that there is still a growing need for an economically attractive process for hydrogenation of esters into alcohols, which should not inevitably require the use of rather pure hydrogen gas, but should be carried out in the presence of cheaper hydrogen containing gas such as synthesis gas or other commercially available hydrogen containing gas mixtures, and should use simpler and therefore cheaper catalyst systems.
Therefore, it is an object of the present invention to provide such an improved process.